Sudoku. Number alone disc surface is a nine, each Palace and is divided into nine a small grid. in this 81 grid in the to out must of known digital reconciliation problem conditions, using logic and reasoning, in other of spaces Shang fill into 1-9 of digital. makes 1-9 each digital in each line, each column and each Palace in the are only appeared once. this game full test do problem who observation capacity and reasoning capacity, although play simple, but digital arranged way is Kaleidoscope, so number alone was think is training mind of perfect way.